Word
effective
Phoneticsef·fec·tive, stress on the first syllable
US/ˈifɛktɪv/
UK/ɪfˈɛktɪv/
Definitions
01successful in producing a result
B1 · Intermediate
adj. producing the result that you wanted or intended.
adj. successful in producing a desired or intended result. Often used to describe solutions, treatments, or methods.
日本語:効果的※
“The new medicine was very effective at reducing her headache quickly.”
“The marketing campaign proved highly effective, resulting in a twenty percent increase in new subscriptions over the first quarter.”
Usage
Commonly modifies nouns like 'method', 'solution', 'treatment', or 'way'.
Pitfall
He is a very effective worker because he never wastes time.
He is a very efficient worker because he never wastes time.
Use 'effective' for things that get the right result; use 'efficient' for things that work quickly without wasting time or effort.
Synonyms
Antonyms
02starting to apply or operate
B2 · Upper Intermediate Law Formal
adj. starting to be used or starting to be a law.
adj. coming into operation or effect; officially in use or valid from a specific time.
日本語:有効※
“The new tax rules will be effective from the first of January.”
“The revised safety regulations become effective immediately, and all site managers must ensure compliance by the end of the business day.”
Usage
Often followed by the preposition 'from' when indicating a start date.
03actual or real
C1 · Advanced Academic
adj. the real or actual situation, even if it is not the official one.
adj. existing in fact, though not necessarily intended or officially acknowledged.
“Although he is the assistant, he is the effective leader of the team.”
“The effective cost of the loan was much higher than the advertised interest rate once the hidden fees were included.”
Teaching tip
In academic contexts, this sense contrasts 'effective' (the reality) with 'nominal' (the name or theory).
Antonyms
04soldiers fit for duty
C2 · Proficiency Countable noun Military Technical · Formal
n. a soldier who is healthy and ready to fight.
n. a soldier or member of a military unit who is fit for active service.
“The general counted his effectives before the morning march.”
“After the long winter campaign, the regiment's total number of effectives had dropped to less than half of its original strength.”
Synonyms
Collocations
Common phrases and expressions where native English speakers use the word “effective” in context.
Verb
01. become effective
“The new tax rates become effective from next Monday.”
verb + adj
02. effective immediately
“The manager has resigned, effective immediately.”
adj + adv
Adjective
03. cost effective
“Solar panels are a cost effective way to reduce energy bills.”
noun + adj
Noun
04. effective communication
“Effective communication is essential for a successful marriage.”
adj + noun
05. effective leadership
“The company's success is due to effective leadership.”
adj + noun
06. effective ways
07. effective at reducing
08. an effective way to
“Walking is an effective way to improve your fitness.”
09. appreciation effective
10. be effective in
“The treatment is effective in treating chronic pain.”
11. effective action
12. effective at doing
“She is very effective at managing large teams.”
Confusables
Effective means a thing works to get the job done, while efficient means it works without wasting time, money, or energy.
RememberEffective = Ends the problem. Efficient = Economical process.
Real-World Examples
“As we report, what began in the 2000s as a geeky way to make charitable giving more cost-effective has changed into a movement that subjects the world to complex, even bizarre, moral calculations.” “On average, students learnt roughly three times more when they received phone calls tailored to their learning levels alongside weekly text messages containing numeracy content than with the average effective education intervention.” Etymology
From French effectif, from Latin effectīvus (“productive; effective”), from efficiō (“I make; I bring about”), equivalent to effect + -ive.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Word family
ADJECTIVE
ADVERB
Domains
- Exam level
- CambridgeCambridgeCambridge English QualificationsThe exam suite from Cambridge University Press & Assessment, from A1 Movers up to C2 Proficiency. The benchmark names double as CEFR labels.B1 PreliminaryIELTSIELTSInternational English Language Testing SystemThe 0–9 band test co-owned by the British Council, IDP, and Cambridge. Used for university entry, work, and migration.4.0–5.0TOEFL iBTTOEFL iBTTest of English as a Foreign Language, Internet-Based TestETS's academic English test, the standard route for US university admissions. Scored 0–120, with a 1–6 scale since 2026.1–6 scale: 3.0–3.544–71TOEICTOEICTest of English for International CommunicationETS's workplace English test, big in Japan and Korea. Listening & Reading scores 10–990 and tops out at C1.550–784
- Frequency
- Very common
- Level
- B1 · IntermediateOxford
- Updated
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QR code
englishreference.com/q/effective
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「日本語」 data: JMdict (EDRDG), CC BY-SA 4.0